1. Field of the Invention
The present invention relates to a ball joint or cap implant for an artificial hip joint that is suited to carry out a rotating or pivoting motion in an artificial hip joint socket, with a gap being provided for a natural fluid film, the synovial fluid, between the ball joint or cap implant and the artificial hip joint socket, and with regular depressions, without interconnecting channels between them, being recessed in areas of its surface.
2. Description of Related Art
A ball joint of this type is known from DE 103 18 374 B3.
A fundamental problem in artificial hip joints is the friction between the components of the joint, the ball joint and hip joint sockets, which leads in turn to wear and tear that can give rise to medical complications.
The invention of the previously cited document was based on the effort to develop a ball joint or cap in such a way as to achieve a minimization of friction and thus a minimization of wear, with significantly reduced manufacturing costs. To do so, it was proposed that, in a ball joint with at least three grooves running in a circle around the polar axis, the grooves are introduced into the ball joint surface without interconnecting channels between them. In this way, a contact surface minimization is achieved since there is no direct contact between the ball joint and the artificial hip joint socket in the area of the grooves. The grooves running in a circle are filled with synovial fluid after implantation. The grooves do not have a buffering effect herein, but rather they perform a weight-bearing role. In addition, due to the fluid-filled grooves, a vacuum is generated between the ball joint and the hip joint socket that represents in turn a significant luxation inhibitor.
Even though this approach was quite promising, it is to be noted that the lubricant effect of the synovial fluid in the gap between the ball joint and the hip joint socket is not optimally exploited to lubricate the ball joint vis-à-vis the hip joint socket, on the one hand, or to carry away any wear particles.
Against this backdrop, the task of the present invention is to propose a ball joint or cap of the type noted at the outset, in which the lubricating and cleaning effect is significantly enhanced compared to the prior art.